Malware (or malicious code) is a catch-all term used to refer to various types of software that can cause problems or damage a computer. The term Malware may encompass viruses, worms, Trojan horses, macro viruses, rootkit malware, and backdoors. Over time, malware has evolved to be increasingly more stealthy and targeted.
Malware has become stealthier by, in some cases, hiding inside the core operating system by infecting kernel modules (e.g., rootkits). Rootkits, especially the ones executing with supervisor or high level privileges (e.g., Ring 0 privilege in the case of Intel Architecture processors) are very difficult or nearly impossible to detect by traditional anti-virus solutions or anti-malware solutions (hereinafter, AVS). For example, rootkits with supervisor privilege and other malware hidden therein may intercept queries from the AVS and feed incorrect information to the AVS to preserve the malware in a storage device.